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Boat anchors: T.M.C. GPR-90 , Johnson Pacemaker, Heathkit DX100

357

Walkin' the dog
Sep 12, 2009
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Chilliwack, BC
www.youtube.com
Just got these in the door, gonna have a heart attack. Frigging heavy rigs.
I will post pics soon.

Anyone interested let me know.
They are in good-very good condition and in a working state.

T.M.C. GPR-90 , Johnson Pacemaker, Heathkit DX100
 
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I’d love to have the DX100, but space is limited. Those home brew rectifier replacements with the top hat diodes were probably made in the late 50’s or 60’s. Since those became obsolete, better diode choices are available, but you can’t discount the visual appearance of the old school top hat.
 
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The Pacemaker was meant as a multimode Ranger, but was a short lived disaster. If you are looking for an AM exciter, skip this one!
If you wish to verify my assessment of the Pacemaker, set it to transmit on 21.0 MHz and listen to the awful birdie that comes out along with the desired signal. Rock the VFO back and forth to be sure you are listening to both of the signals. There are lots of decent fun legacy SSB radios to play with that will not get you an OO report or a QSL card from the FCC. Avoid this one.
Info above copied de:
http://wireless-girl.com/Projects/AMTransmitters/JohnsonPacemaker.html

Unfortunately the Pacemaker, while made by one of the Best...E.F. Johnson was not their greatest achievement...Though sought after by some collectors, more of a display to collections than a widely used Transmitter.
Whether a transmitter is "a good one to restore" depends on what you want to do with it after it is restored.
The Pacemaker was Viking's first SSB transmitter and has a single 6146 for a final. So the INPUT power is 90 watts SSB and CW and 35 watts AM.
The output will be maybe 50 watts which is enough to use barefoot or with an amplifier on SSB and CW.
On AM its power is not much particularly with the bands in the shape they are now.
GL
All the Best
Gary

Model: Pacemaker - Johnson Company, E.F.; Waseca,
Material Metal case
Shape Tablemodel, low profile (big size).
Dimensions (WHD) 21 x 11.6 x 16.6 inch
Notes AM/CW/SSB transmitter for 80-10 m amateur bands. 35/90/90 watts input.
Net weight
73 lb 12.6 oz (73.789 lb)
 
  • Like
Reactions: 357
The Pacemaker was meant as a multimode Ranger, but was a short lived disaster. If you are looking for an AM exciter, skip this one!
If you wish to verify my assessment of the Pacemaker, set it to transmit on 21.0 MHz and listen to the awful birdie that comes out along with the desired signal. Rock the VFO back and forth to be sure you are listening to both of the signals. There are lots of decent fun legacy SSB radios to play with that will not get you an OO report or a QSL card from the FCC. Avoid this one.
Info above copied de:
http://wireless-girl.com/Projects/AMTransmitters/JohnsonPacemaker.html

Unfortunately the Pacemaker, while made by one of the Best...E.F. Johnson was not their greatest achievement...Though sought after by some collectors, more of a display to collections than a widely used Transmitter.
Whether a transmitter is "a good one to restore" depends on what you want to do with it after it is restored.
The Pacemaker was Viking's first SSB transmitter and has a single 6146 for a final. So the INPUT power is 90 watts SSB and CW and 35 watts AM.
The output will be maybe 50 watts which is enough to use barefoot or with an amplifier on SSB and CW.
On AM its power is not much particularly with the bands in the shape they are now.
GL
All the Best
Gary

Model: Pacemaker - Johnson Company, E.F.; Waseca,
Material Metal case
Shape Tablemodel, low profile (big size).
Dimensions (WHD) 21 x 11.6 x 16.6 inch
Notes AM/CW/SSB transmitter for 80-10 m amateur bands. 35/90/90 watts input.
Net weight
73 lb 12.6 oz (73.789 lb)

This one has many mods, maybe fixing the birdies?
L8 is shielded with plexiglass, T1 audio transformer is replaced with that gray round one and this unit has 2 final tubes in it.
Maybe someone made it work better than when it left the factory?

Wireless girl isn't the world expert on johnsons is he?
 

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